1986 4Runner Base

My rear window works up and down with the key in the tailgate but only down with the switch in the center console. I have the FSM and read through 4Crawlers site about the window then did some investigation last night and found the following:

• Voltage readings are all inline with the FSM except for up/down on both key and switch
  • All are supposed to read 12V but instead read +/- ~100mV (couldn't figure out the "-" ones as the ground probe stayed in the same spot)
  • When activating the key or the switch, the Voltage goes to exactly 0V
• Because the switch works for down and not up, I checked the resistance when the switch is activated. Both up and down read identical at 4 Ohms
• I can audibly hear and physically feel the relays clicking when the switch is used for down or the key is used for up/down. Nothing happens when the switch is used for up. I dismantled the switch and saw the copper pad was black for the up position. With some light sanding, I made that shiny again but there was no change.
• Relay box/circuit card are clean and in great looking condition

I'm at a loss for what the problem could be. Has anyone else experienced this? I'm hesitant to buy a new switch when they're $70-100 or a new relay box for $200 when both of seem to be working (and it doesn't affect the driving experience). If that IS the solution then no up will just be the way it is.

 

I just went through a similar issue. I'd check for continuity in the red-yellow wire between the switch and the relay, but first I'd push the pin out of the switch and clean it. Mine had a broken G-Y wire which is down. There's a thread from a week ago with posted schematics.
https://www.yotatech.com/forums/f116...ration-317148/

 

So I know I have continuity in all the wires, I have the electrical FSM and followed that procedure (R-Y has the exact same Ohm value as G-Y = 4 Ohms when the switch is pushed). I'm thinking cleaning all the connections is the next thing I try though. Make sure all the grounds are all set.

New issue as of yesterday afternoon was that the window stopped working entirely. Remembered about the circuit breaker under the dash and reset that and it didn't start working right away. When using the key, the relay box started buzzing; the switch didn't do anything up or down. I went back to the relay box and just squeezed the connector and then everything started working fine (didn't click any farther in). However, this buzzing happened the other day as well but in the middle of testing and then no buzzing or rolling up/down. I didn't remember about the CB at the time so I took off the tail gate panels and just touched everything with my fingers and then it started working again (makes me think the CB didn't trip the other day). Starting to think I should clean everything up and then try again. It used to work without fail before I started trying to fix the up switch!

 

Does anybody know where and how the limit switch works for the rear window? I see a switch type device that has a roller on it that rolls along the gear for the rear window but from what I remember, the roller never falls off the gear. Wondering now if I have a bad ground somewhere near the rear window. Just at a loss since I was able to get connectivity when using the console switch but no activity.

 

Drop the rear wiper cover and short the contacts to eliminate the wiper 'park' issue. That will allow the window to go down and not up.

 

Those have already been shorted, found that trick when I first got the truck from my dad and didn't want to use the jerry-rigged wires that went from motor to battery. This was a good reminder that I hadn't actually plugged the wiper plug back in. Did that but no luck there. I tested the plug at the motor and the motor is getting 11.5V through the regular circuit. The relay doesn't buzz when the motor isn't attached. Hooked up the motor to the battery again and it does work but when its plugged in through the circuit, not only does the relay buzz but the motor housing vibrates as well. perhaps its just a bad motor? or maybe its simply not getting enough voltage?